1. Field
The present application relates to an electric pump, and more particularly, to an electric pump pumping a fluid through a rotor rotated by a motor.
2. Background
In general, electric oil pumps (EOP) are devices for supplying, using a motor, oil to an oil pressure line in a transmission or a braking device of a vehicle in which an oil circulation is required.
In the case of hybrid electric vehicles (HEVs), since an engine is halted when a vehicle is not travelled, it is difficult to supply a predetermined pressure to a transmission through a mechanical oil pump. Due to this, an electric oil pump which supplies oil through a motor is used in the HEVs.
Torque of such an electric oil pump is generally classified into hydraulic torque due to a volume of a fluid and friction torque due to mechanical friction. Once the friction torque is increased, since a loss due to the friction should be compensated, additional power is required and electric power consumption of the electric oil pump is thus increased.